Secure and efficient public key multi-channel broadcast encryption schemes

In the modern era of digital technology, sending different messages to different group of users are essential in many real-life applications, like TV broadcast, radio broadcast etc. Multi-channel broadcast encryption (MCBE) is a mechanism which sends different messages to different group of users efficiently. We have proposed two multi-channel broadcast encryption schemes in the public key setting. Our first construction is selectively secure against chosen-plaintext attack, whereas the second one achieves adaptive security which is the strongest security model in the broadcast setting. Besides, our second construction is dynamic, whereas none of the existing MCBE constructions supports the dynamic property. Moreover, our second MCBE construction is the first inclusive-exclusive MCBE construction, where the broadcaster can reduce the encryption and decryption cost by choosing the smallest set between the set of subscribes and revoked users in the encryption and decryption phase respectively. (C) 2019 Elsevier Ltd. All rights reserved.